Registering tourniquet applicable for the determination of blood pressures



y 1940- E. J. LA LIBERTE 2.199.408 REGISTERING TOURNI UET APPLICABLE FOR THE DETERMINATION OF BLOOD PRESSURm Filed Sept. 2'7, 1937 l/lI/IIIIIII/II/ I91111111111111III/1111111119111111111111], I 'IIIIIIIIIIIIIIIIIIIIIIIII/ V Patented May 7, 1940 REGISTERING TOURNIQUET APPLICABLE FoR THE DETERMINATION OF BLOOD PRESSURES Elie J. La Liberte, Worcester, Mass, Application September 2-1, 1937, SerialNo. 165,860

1 Claim.

The principal object of this invention is to provide an arm or leg band for use as a registering tourniquet, such tourniquet also being practical for the determination of blood pressure.

Other objects of the invention are to make a bag of a thin membrane that will be flexible enough to transmit heart beats to the fluid contents of the bag but which will not stretch outwardly and at the sides when air or fluid is applied to the bag; to eliminate such stretching and thereby losing of impulses and pressure, the bag is reinforced on its outer surface in the form of a strong enough strip of fabric, or rubber, or a combination of both, which will serve such purposes as,'i. e., to preserve the flexibility of the outer portion of the bag so that it will take the contour of the limb so as to serve as means of attaching said band, and to provide on said strong strip on theoutside, two nozzles, one, for a bulb to. provide air or fluid to the bag, the other, to connect with a pressure gauge for the purpose of determining the pressure and pulsa-' tions from the contents of the bag.

This band, being primarily a tourniquet, is sturdy and narrow. If liquid is used as the content of the bag, the band can be made still narrower than represented by the figures given below, because of the better transmission of impulses due to the lesser compressibility of fluid as compared with air.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawing, in which Fig. 1 is a plan of the entire band laid out straight and not in operation;

Fig. 2 is a side view of the same with the air pressure gauge and bulb;

Fig. 3 is a plan of a somewhat modified form, useful with a blood pressure apparatus;

Fig. 4 is a sectional view on the line 4-4 of Fig. 3;

Fig. 5 is a sectional view on the line 5-5 of Fig. 3, and

Fig. 6 is a view showing the instrument as ap- (Cl. 128-2415). q

long, enclosed in a cloth bag through which much of the impulse is lost. The cloth bag-is wound aroundthe arm or leg several times and serves rather suitably for thin limbs, but for short fat limbs, it has a tendency to roll and the disadvantage that it is likely to cover a vein, or a field, which is being tested for pressure or about to be opened for some surgical operation and in that case it is likely to cover also some of the sterile field. For that reason this armband, which is used for manometers, is seldom or never used as a tourniquet for the stopping of the veinous flow and allowing the arterial blood to fill the vein in the arm or other limb before introducing a needle. It is seldom or never used as a tourniquet to shut off completely the arterial circulation in case of amputation or other surgical procedures. The ordinary form of tourniquet'has nothin membrane to transmit pressure to a bag nor is it equipped with a gauge, and it provides no means of indicating whether the blood flow is shut off or not.

By this invention the old winding, cumbersome cloth bag is eliminated, though a covering may be used to preserve the rubber in delaying oxida- Y zation and so prolong its life. The inner surface of the band is formed of a narrow,. very flexible, rubber membrance I0, formed of a compound which will be flexible enough to readilyv transmit the cardiac and pulse action to the contents of the bag. The outer surface ll of' the bag is formed by a strip of rubher, or fabric, or a combination of both, of the same width, but of greater thickness, which strip encircles the arm and is much more rigid and serves to prevent the impulses from being lost by the stretching of the bag. This fabric II is passed exactly once around the limb and its two ends are secured directly and positively to each other. This can be done in any suitable way. One way of doing this is to provide two series of button holes l2 on one end and a pair of buttons l3 on the other end to engage with the where they are held rigidly, and are located in any convenient place.

This bag may be two and a half inches wide or thereabouts and eight inches long, more or less. The inner membrane In is to be placed against the arm. It is made of a flexible gum compound approximately one thirty-second of an inch in thickness. The outer rubber H is to be made of a strip of less flexible rubber compound, about one-eighth of an inch in thickness. This outer strip will be made in semi-elliptical shape, tapering to the inner membrane. The depth of the air or liquid pocket of the bag surface between the parts l0 and H may conveniently be about one-quarter of an inch. Two tubes l9 and 20 are used to connect the nozzles with the air or liquid bulb and the gauge respectively.

This description is applied to the construction in Figs. 1 and 2 which is useful both as a blood pressure appliance as well as a tourniquet.

The construction disclosed in Figs. 4 and 5 can also be used for both purposes, the operation be- 7 ing the same as in Figs. 1 and 2, but the construction differing in the fact that the bag shown in Figs. 3, 4, and 5 is not designed to be secured at its ends by the buttons l3.

It will be seen that an arm band constructed, as stated, is not only more suitable for use with a manometer in a blood pressure testing apparatus but it is also better as a tourniquet than those now in use. This device will transmit to the registering instrument all kinds of records of cardiac action, which can be observed on the pressure gauge, the range of which will be very much increased, thereby facilitating observation, giving information about the heart, the blood pressure and the condition of the artery.

This invention provides an accurate method of determining the shutting off of the veinous flow, this determination being possible by reason of the pressure gauge needle which will oscillate at the very onset of interference with the veinous flow and the oscillation will increase somewhat until the veinous flow is completely shut off. As soon as the oscillations are well established, the complete cessation of the veinous flow is indicated.

An accurate method for the determination of the shutting off of the arterial flow is also provided by this invention, i. e. the interference of the arterial flow is shown by the diminishing of oscillation of the pressure gauge needle, under increased pressure, and the complete shutting off of the arterial flow by the cessation of oscillation of the pressure gauge needle under increased pressure.

By the use of a stethoscope with this invention, a thud will be heard with the interference of the veinous flow which will increase in intensity as the veinous flow is completely shut off. On the contrary the diminishing of the thud with increase of pressure determines the interference with the arterial flow and the complete elimination of the thud shows the arterial flow has been shut off. To accomplish this reaction, the stethoscope must be placed over the main vessels below the application of the arm band. The above data gives all information necessary in case one wishes to gorge a vein for the intro,- duction of a needle, as in blood transfusions, or the drawing of blood, and the like, or to shut off the flow of blood for amputations or other surgical operations.

This invention also determines more exactly the pulsation, and the veinous and arterial pressures by eliminating much of the loss of impulses and pressure due to the present arm bands now in use.

This instrument is a compact and workmanlike device which performs its function extremely well and is the only practical registering tourniquet known. It is easily made, requires little material, and performs its action better than heretofore any other instrument has done.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claim, but what I claimis:

As an article of manufacture, an air or fluid bag comprising an inner membrane of'very thin material adapted to transmit pulsations from the blood flow and heart beat of the human body to the contents of the bag, said bag having an outer wall of substantially the same width, but of greater thickness and rigidity, spaced from the thin membrane, a nozzle supported in the thicker strip for attaching a bulb to introduce thepressure, and means mounted on the thicker strip for connecting a pressure gauge, said gauge indicating, by the oscillation of its needle, when the veinous flow has stopped, and indicating, by diminishing oscillation, interference with arterial flow and finally, by cessation of oscillation, that the arterial flow has stopped.

ELIE J. LA LIBERTE. 

